Inverter devices for controlling power to be supplied to an electric motor have heretofore been known. Such an inverter device includes an intelligent power module (IPM) including a semiconductor chip serving as a switching element such as an IGBT (Insulated Gate Bipolar Transistor), an inverter circuit board on which the semiconductor chip is mounted, and a control board for controlling driving of the semiconductor chip.
The intelligent power module is provided with an output electrode which outputs power of the circuit board. The inverter device is provided with an output terminal which outputs its power to an electric motor. There are examples in which the output electrode and the output terminal are electrically connected through a bus bar serving as a relay-connecting member. Specifically, one end of the bus bar is fastened to the output electrode (for example, a bus bar) by means of a bolt, and another end of the bus bar is fastened to the output terminal (for example, a bus bar) by means of a bolt so that the output electrode and the output terminal are electrically connected.
Further, there are examples in which the relay-connecting member is provided with a current detector which detects a current that flows therethrough. The current detector includes a core through which the bus bar is passed, a magnetic flux density detection element such as a Hall element which is arranged in a gap portion of the core, and a circuit board on which the magnetic flux density detection element is mounted. In this current detector, when a current flows through the bus bar, the current causes generation of a magnetic field within the core, and the magnetic flux density detection element converts the intensity of that magnetic field into a voltage signal to thereby allow detection of a current value.
JP 2006-194650 A describes a current sensor which is accommodated in a power converter, and which detects a current of a bus bar that connects a semiconductor module and an output terminal block. The current sensor has a case which is formed of a resin such that the bus bar and a core through which the bus bar is passed form an integral structure, and a Hall element and a circuit board are attached to this case.